CASE STUDY

4x4-Off-Road-Driving_lrg

OpenECU Platform Used to Develop Torque-based Traction Control

Challenge

Pi Innovo was asked to provide traction control based on output torque management from front, rear and center differentials of a light-duty 4WD vehicle to increase off-highway mobility and performance.  Prior to the development of this system, the vehicle was configured for full-time 4WD with open differentials.  This previous configuration required the driver to modulate any wheel-spin by use of the brakes, requiring extensive driver training and an increase in driveline wear-related maintenance.

Solution

Pi Innovo’s engineering team used the OpenECU rapid controls prototyping platform to develop custom vehicle control systems algorithms to provide individual wheel torque management via hydraulic-controlled limited-slip differentials.  Inputs were individual wheel speeds, overall vehicle speed, steering position, transmission gear position, and driver torque demand (accelerator pedal).  The control software balanced the torque being provided to each wheel based on differences in individual wheel speeds by controlling the outputs of the three differentials to balance traction wheel-to-wheel on each axle and front-to-rear overall.

Results and Impact

This system allowed the vehicle to be driven on loose surfaces without any one wheel breaking traction and provided the ability to climb gradients and control wheel-spin without the need for manual breaking.  The system was run in a comparison test with a standard vehicle and the results indicated a superior ability to climb a loose-surface gradient (using an untrained driver) with a corresponding increase in overall vehicle mobility and a reduction in likely wear-related maintenance.

Project Features

Vehicle systems development
OpenECU rapid control prototype platform